The mysteries of rabies

One day, towards the end of summer, I walked into my living room and found my cats playing "Secret CIA Prison" with a bat. He was alive, but just barely. He lay on my floor twitching, his wings torn to Swiss cheese. The cats looked up at me as if to say, "We do good work, yes?" I locked them in the bedroom and called the vet. Fortunately, the cats were all up on their shots. Unfortunately, I couldn't tell the vet how the bat had gotten into the house, nor how long he'd been there.

"You should maybe call your doctor," she said.

On average, 55,000 people worldwide die from rabies every year, but only two or three of those cases happen in the United States, thanks to widespread vaccination of domestic animals and availability of post-bite treatment for humans. Today, when Americans die of rabies, it's usually because they didn't realize they'd been bitten until it was too late—which is to say, when they first noticed symptoms.

See, we know how to prevent rabies, but we have absolutely no idea how to cure it. In fact, we don't even really know how it kills people. Despite (and, perhaps, because of) its status as one of the first viruses to be tamed by a vaccine, rabies remains a little-understood disease.

It's a mystery that makes doctors understandably nervous. Just a week before I found my bat, some friends of mine in St. Paul had woken up to find a bat in their bedroom. Being asleep is one of those times when tiny bat teeth could bite you without you being aware of it. My friends had to get post-exposure prophylaxis, a treatment designed to neutralize any rabies virus in your system before it has a chance to reach your brain and develop into a full-blown infection.

"You think about flu, that's a very quick virus. You develop symptoms in a couple of days. In a week, it's passed. But rabies incubation is very long," said Zhen Fu, DVM Ph.D., professor of pathology in the College of Veterinary Medicine at the University of Georgia. "It may be weeks or even months before you develop an active infection. So we have enough time after a bite to immunize with normal vaccine and bring up the immune system."

That means five doses of vaccine, over the course of 28 days, according the Centers for Disease Control and Prevention. If there's also an obvious bite, doctors will clean the wound and apply rabies antibody serum to the site. The antibodies are basically the key part of a lock-and-key system that tells your immune system to destroy anything the key fits. The idea is that antibodies will help destroy most of the virus at the site of entry, while the vaccine will train your body to knock out any strays it finds elsewhere. The CDC also recommends a shot of antibodies, separate from the vaccine, even if there is no obvious bite.

This one-two punch is almost 100% effective, provided you get it in time. How fast is "in time"? Nobody really knows. The CDC says that, as long as a bite victim isn't yet symptomatic, they should get the prophylaxis. Dr. Fu said that the window of opportunity can vary in length, depending on how close the bite is to the person's central nervous system. Without post-exposure prophylaxis, rabies is fatal. By the time symptoms--fever, confusion, partial paralysis, difficulty swallowing--appear, it's too late. There's not much doctors can do after that, because they aren't even sure what the virus is doing to you.

"We don't know how rabies kills people. There are some unproven hypotheses, but that's it," Dr. Fu said. "One idea is that, once the infection reaches the neurons in the brain, it blocks the transmission of messages from the brain to the rest of the body. If that's the case, it could explain many of the phenomenon we see in humans and animals, such as end-stage paralysis. That could even be why humans die, because of paralysis of muscles in the heart and lungs."

Given the lack of information and the risk of death, it's not surprising that even a situation like mine, where a bite was extremely unlikely, ended with a referral to a nearby hospital for post-exposure prophylaxis. But, after several conversations between the emergency room doctor and the Minnesota state rabies hotline, I ended up not getting it. Turns out, sneak-attack bites don't really happen to wide-awake, sober, cognitively normal adults in the middle of the day. The chance that I or my husband were actually bitten by the bat before the cats set upon it was so small that, on the advice of medical professionals, we decided that it wasn't worth the pain, potential side-effects, or cost of treatment.

That's right. I am my own death panel.

But on the off-chance that I do come down with symptoms—there've been cases of rabies incubating for up to a year—is there really no hope? Well, sort of. Maybe. Ish. Researchers have been experimenting with a treatment that they think could save the lives of people with full-blown rabies. Called the Milwaukee Protocol, it involves putting the patient into a coma and also giving them antiviral medication. The idea is that the human immune system—with some help from antivirals—can fight off a rabies infection, while the coma limits damage to the brain that seems to be a common cause of rabies death. In 2004, a teenage girl who received this treatment became the first person—ever—to survive symptomatic rabies without having received the vaccine either before being bitten, or before symptoms appeared.

The problem: We still don't know whether the Milwaukee Protocol actually works. It's been tried—and failed—at least 13 times since 2004, according to a 2009 paper published in the journal Current Infectious Disease Reports. There are two reported successes, but in one of those the patient received the vaccine before her she became symptomatic. The other success is very recent and there aren't many details available yet.

So why did the first girl survive? Again, nobody knows. It's possible that either she had a particularly hardcore immune system, or the variant of the virus she contracted was particularly weak, or both. When she was diagnosed, she had rabies antibodies in her cerebral spinal fluid—something that would indicate the presence of rabies in her brain—but doctors weren't able to isolate any actual virus—suggesting that her body was already on its way to winning the fight before the Milwaukee Protocol was used.

Unfortunately, any effort to really conquer rabies may be hampered by the fact that the vaccine works so well, Dr. Fu said.

"Treatments haven't been successful because we don't know what it's doing in the brain," he said. "We need more research but, usually, once you have a good vaccine the funding for the research goes away."

62 Responses to “The mysteries of rabies”

Recently watched a program on RFDTV regarding rabies vaccinations for horses. I had not even thought about horses being susceptible, and of course if a horse gets bitten no one is likely to notice until they start showing signs, and the signs do not necessarily point you right to the conclusion of rabies. So by the time they are properly diagnosed there are usually a lot of people who will need treatment for exposure. Just the thought of something which is incurable and fatal is so horrifying. It’s easy to forget life really is precious and delicate.

Next time a bat gets into your house, how about just catching it and putting it back outside? Rabies is fairly rare in bats, and they’re amazing and very useful animals. At the very least, it concerns me that you have kids who think beating ANYTHING to death is a good thing.

Vampire bats are particularly effective at transmitting the virus, but their range is pretty limited. Other bat species don’t seem to have the same resilience in the face of active rabies, so they lose the fine motor control necessary for a bat to do more than crawl or flop around on the ground pretty quickly. The majority of confirmed non-vampire bat-transmitted rabies cases involved people who were bitten after harassing or trying to assist bats that were clearly incapacitated.

Wow. Bats seem to be getting a bad rap on this thread. Rabies is bad, no question. But are bats really that common a carrier? I live in Ohio, and had the chance to talk to a local wildlife vet recently who told me that rabies in any animal is very uncommon in my state – largely due to a long history of good control measures. I know that raccoons and skunks are common carriers – anything big enough to survive an attack by a rabid carrier. It’s pretty uncommon in rats, because of their size. But does anyone know the incidence in wild bats?
Oh wait, I’ll ask the Internet…

Ok. So one in five bats has rabies. Not good odds. But on the bright side, it’s pretty uncommon to catch rabies from a bat flying in your house.

(As a side note: An effective rabies vaccine has been developed, using gene therapy, that puts the genetic code for a vaccine into an orally-available virus which then “infects” an animal that eats it. Really cool stuff.)

As a slightly orthogonal link, the first collection of short stories (called “Lantern Lecture” in the UK, “Fabrications” in the US) by Adams Mars-Jones, a college-era friend of mine, includes “Hoosh-mi,” a [briefly notorious] imagining of Queen Elizabeth II succumbing to bat-borne rabies.

I woke up at 2am one night this summer and found my cats tossing around a wee little bat who was still squeaking and mad and alive. We wrapped it in a towel and tossed it outside, the cats were so disappointed.
I don’t take my cats to the vet for regular vaccinations because they are strictly indoor cats, but we took the one who had been obviously playing with the bat. The vet told us that Seattle bats rarely have rabies so its also unlikely the cats would have been infected. All in all, I was pretty scared that my poor cats would die a horrible rabies death until the vet made us feel better. Its been 7 months or so, both cats are fine.

Hah! My sisters and my mom and I were just talking about rabies the other day while playing “If you where a disease/virus/infection, what would you want to be?” at the dinner table.

There are only a few people who have survived and I believe they mostly have suffered serious permanent brain damage. The one or two exceptions where put in a induced coma to stop the progress of brain degradation while giving the treatments time to work, I believe. The survior’s cases were fairly recent too; sometime in the 00’s.

I remember a few years ago some little kid at the Minnesota Zoo tried to pick up one of the meerkats or groundhogs and got bit. They put down the animals to check for rabies instead of treating the kid which I thought was sort of cruel.

Great job demonizing bats, who are already suffering an unexplained plague of fungus (75% of White-Nosed Bats have been obliterated recently, and suddenly). As if bats getting into your house are the #1 way to get rabies. Raccoons, opossums,and skunks are far more likely to give you rabies than a bat!

Depends what part of the country you live in. in California, at least the part that I live and work (animal control) in, our leading rabies carriers are bats, with skunks coming in second. Raccoons very commonly carry it on the east coast, but not around here. Opossums, while they have been known to have rabies, are much less likely to have it than any of the listed animals. they have an immune system that works differently from the other animals. Because a bat can get into your house without you noticing, can bite you in your sleep without you feeling it, and can carry rabies with no symptoms, they are a much bigger risk than other animals. Don’t get me wrong, I love bats, and all animals, but downplaying their risk is dangerous.

Just an FYI– there is a lot of paranoia in these stories about bat-transmitted rabies. (The author, BTW, does not seem to be one of the paranoid.)

I’m not saying it never occurs, just that the it appears wildly overblown. Generally, when someone, particularly a child, gets rabies and no one can find the proximal cause, bats are assigned the blame– even though, as this article said, the incubation period for rabies is up to a year and all sorts of animal contact occurred over that period of time.

Bats are actually under a lot of ecological pressure these days, both from encroachment and “prophylactic” extermination. They are by far the most effective natural check against mosquitos– no small spreader of fatal diseases themselves.

I expect there’s some correllation because rabies seems to knock down bats faster than normal — especially because they’re so small and there’s not much nervous system for the disease to rampage through — and because bats need every bit of nervous system working in order to fly properly.

Children, this is WHY you don’t touch wild animals except with heavy gloves or better yet find a professional to deal with them. And why you vaccinate your pets, even indoor kitties who never, ever get out — sometimes the outdoors comes in to THEM.

Just went through the 5 shot series after exposure to a Raccoon. In the 80’s I had the RIG which would have allowed me to only get 2 post exposure shots instead of 5. They couldn’t track down the record so i got a RIG and the 5 shots..sucks.. but beats croaking .

Really, the lack of funding makes a ton of sense to me – in the US at least. Once an almost completely effective treatment is in place, with the number of deaths down to a really tiny amount, why should much money be spent on studying it? That funding is better used to study something that’s still affecting thousands of people each year.

Then again, understanding how it works might help push our understanding of other diseases, so maybe I’m talking myself out of that position.

Maggie, thanks for the interesting post! I’ve also had a bat in my house and didn’t worry about getting a rabies shot. The thought hadn’t even crossed my mind, honestly.

a very good article. people love pets, but they do not know the danger at the background of this love. rabies is an incurable viral infection. but there are many safty steps to be followed by pet lovers. this valuable article makes the reader understand how much terrible rabies is

If you find a potentially rabid animal, they can test it, sparing you the nasty series of shots. However, the test is lethal for the animal.

Before we vilify bats, people need to realize that domestic animals can become infected. And because we bring them into our barns and homes, we’re more likely to get in contact with their saliva. For example people who feed stray cats but who won’t take them to the vet are creating a wonderful potential for rabies. Dogs of course are also a risk. Livestock can get rabies; there is a case of a rabid calf at an education center here in Maryland in December. If you’re not sure an animal is vaccinated, assume he isn’t. And get ALL animals on your property vaccinated, even the “barn cats” who come and go.

Rabies vaccinations are as cheap as $5. Call your local SPCA or health department and ask about “rabies clinics”. Dog/cat rescues may also be able to help you.

Thanks for finding it and putting it to use, but bats aren’t a good way to get rabies. Many other animals are vastly more likely to be rabid.
It is a pretty dramatic face though; not something you would want to stick any soft parts into. Heh.

Raccoons are much more likely to have the disease. I worked at a swimming pool where some tenants had adopted a wandering raccoon, and they took it to the pool frequently. They had a large party with over a hundred guests, sharing beer with the critter…. then it got sick, they took it to the vet, who dxed rabies, and there was a small media blitz in Baltimore to try to get everybody who’d partied with it to go get the shots. (I tried to get a phone line out to the health department to see whether pool patrons should be concerned, but got canned instead.)

In the late 70’s, I was working at Albany Medical Center, in Albany, NY and a researcher at the hospital got rabies. He’d been working with the live virus, but they didn’t really know how he contracted the disease. There was quite a bit of concern that he may have inhaled it. Anyway, I took care of him in ICU, and he survived, although he had permanent brain damage. We were under the impression that he was the first person to survive rabies.

@Geonz: the ‘most likely carrier’ varies by geographic region. In my corner of the US, skunks are most the most likely animal to have rabies. The most common reservoirs in other areas include foxes and raccoons. Bats aren’t #1 anywhere (a close #2 in some spots), but they’re worrisome since, as previously mentioned, in rare cases, they may expose people without their knowing.

This is apropos of nothung sensible in the way of comments… have lived deep in the bush here in OZ, but never saw a bat. Lots of spooky looking owls though. They sit so still on any wires around and I actually love their ‘boobook’ noise. Possums.. how possums ever got into our cupboards is a mystery. I was just thinking, to veer back on topic, that the bat has become such an Avatar for kids today, from comics etc. AND never forget the influence that the Twilight series will have on these creatures of the night!!

It’s worth noting that Preventive Vaccination is available for humans, however it is not generally recommended except for people who are likely to be exposed to animals who might be infectious (vets, animal control, etc) and is expensive; it’s 3 doses over a month’s time, as opposed to the 4 doses (plus a shot of Rabies Immune Globulin, for a total of 5 needle sticks) you would receive post-exposure.

And just like with your pets, even though you’ve been vaccinated they still recommend post-exposure prophylaxis, so getting vaccinated in advance doesn’t really cut down on the number of injections you’d need, so it’s just not worth it unless you’re in a very high risk group.

Very interesting, thanks Maggie. I had no idea it was still such a serious disease (if you don’t get the vaccine). Raccoons are definitely the big scare around here, not bats, especially when raccoons and domestic animals can easily get into fights right in your back yard.

Highly recommended reading: Berton Rouche’s essay _The_Incurable_Wound_. (It’s the title chapter of one of his books of collected essays.) Rouche did a wonderful job of presenting the history and current state of medicine in the form of “whatdunnits”, using real-life cases as a springboard for illustrating how far we’d come and just how fragile a thing life still was (and is). _The_Incurable_Wound_ is his description of rabies, and even though it was written half a century ago this is one area where we haven’t made all that much progress.

(I’ve often thought that more game designers should read this one. D&D players in particular tend to be very cavalier about how their characters are getting clawed and bitten, and a bit of infection risk — either real-world hazards or fantasy ones like infectious lycanthropy — would make the gaming worlds that much more complex and interesting. “Never mind protecting the code — protect the healer!”)

We once woke up to find a bat had gotten into the room. While we didn’t feel that bites were an issue, we did notice that were dozens of little bat poops (just like those of non-flying mice) all over the covers, and we hoped that we hadn’t been sleeping with our mouths open.

Australians, you aren’t really rabies free! Australia has the bat lyssavirus (which belongs to the same genus as classical rabies, just a different genotype), which has the same transimission, symptoms, and fatal outcome. Fortunately the same vaccines and prophylactic procedures as rabies protect against it, so it’s all good.

Raccoons (also coyotes, foxes, skunks) often die from “canine distemper”, symptoms of which are very similar to rabies. (Canine distemper is _not_ transferrable to humans.) Good to be cautious, but if you see a raccoon who seems to be rabid, it is more likely that he is infected with canine distemper.

Maggie, thanks for this timely article. I was recently trying to raise awareness of rabies among my friends, and I had the thread hijacked – hijacked! – by some Tetanus Awareness lunatics. (Hopefully that won’t happen here.) While there are more tetanus deaths in the US (and world) per year, you can have symptoms of tetanus, go to your doctor, get treatment, and live. With rabies, the onset of symptoms means it’s already too late, which is why I am morbidly obsessed and obsessively terrified of this disease. I might already have rabies!!!

I hope that you, as a Minnesotan, are also aware of the threat of Bubonic Plague aka Black Death that is carried by the Prairie Dogs of your state (and the Dakotas). Please be safe!

i once read a news article where someone died because he didn’t get the vaccine after catching a bat in the house and setting it free. he didn’t think he needed the vaccine because he was sure he hadn’t been bitten.

as to how he got it, i think the article said something about getting some of the bat’s saliva on him or something. not to scare anyone, but i just wanted to let you know there might be a possibility of getting it without being bitten at all.

Opossums aren’t a likely rabies vector, according to the University of Florida:
“Opossums, like most other animals, are susceptible to infection by the rabies virus; however, very few rabid wild opossums have been documented. Extremely high doses of the virus have been required to experimentally infect opossums as they seem to be highly resistant to the disease. Even though they do not often carry rabies, opossums can still deliver a nasty bite.” – http://edis.ifas.ufl.edu/uw026
There’s some speculation the marsupial’s low body temperature inhibits the rabies virus’ growth.

Exposure to rabies can happen any day, any time, and at the places you expect the least. In the last 3 days, there were more than 20 incidents of rabid dog biting in moscow (the place is not exactly the middle of nowhere – it a large megapolis). I’m sort of scared now to go outdoors.

as an aussie, I want to remind my fellow aussie that hendra virus is a near-rabies equivalent and that the treatment regimes and prophlaxis are mostly the same..

fruitbats being somewhat larger than these critters, and having more liquid acidic fruitshit (it strips the duco off cars) the prime target is horses, eating grass under fruit-trees where fruitbats feed.

hence hendra: the Brisbane suburb where the racehorses live, who first infected and killed a trainer..

I’ve just had a course of five, which was prompted by a nip from a stray cat, which I feed, here in India. It’s one of those injections that makes your muscle ache for a few minutes, but it was gone by the time I walked out to the car. No pain; no side effects.

The cat continues to be fit, so I’m confident I would have been anyway. Plus rabies is not common in this city. The casualty doc said didn’t need rabies jabs, but I said I wanted them.

Interesting post! Rabies was my number one concern when I was doing the veterinary thing in the Army. In fact, digging up some information on the first positive rabies case reported in the upstate NY/Canada area, you’ll find my name. Prior to my sending a suspicious raccoon in there had never been a positive case in upstate NY, and that area of Canada, until that point, was considered “rabies free.” It even sparked a rabies vaccination bait drop that I took part in. (Flying in a small bumpy plane with hundreds of pounds of fish-smelling baits… I was one of the few that managed to come down with a clean barf bag.)

So all that being said, I’m curious as to why they didn’t have you send the bat in for testing? This would have removed any doubt one way or the other, and would have allowed you to make a more informed decision.

Personally, Rabies scares the hell out of me. My rabies titer is 14x stronger than what is considered “immune” and even still, I pay for the occasional booster. But then, I also enjoy hiking/camping quite a bit.

Hey anonymous. If i had the 5 post injections, then two boosters after 4 years, then another 2 after another three, ive been told i will be immunized this time for more than 5 years this time (CDC recommendations). WHen you say your titer is 14X the immunized level how many vacciniations have u had? and where do u htink i stand based on the vaccines ive gotten?

Opossum dropped (literally) dead in my back yard this fall, of presumably natural causes since I didn’t notice any marks when burying the corpse. Of course I didn’t see it much closer than the end of a shovel, since I didn’t know what it died of and didn’t particularly want to get closer. But I’m wondering whether there will be a point at which it could be presumed safe to exhume the bones and mount them for display — or whether I should abandon that idea.

(I considered trying to find a taxidermist, but presumed that they too would rather not work with the remains of a critter in unknown-but-suspect health.)